4 - Legislative Council Select Committee on Building Problems of Public Housing Units

Legislative Council Select Committee on Building Problems of Public Housing Units Chapter II Tin Chung Court incident - Background and management structure Background 2.1 Tin Chung Court was part of the Tin Shui Wai Area 31 Phase 1 development, which was incorporated into the Hong Kong Housing Authority (HA)'s Public Housing Development Programme in June 1993. The project aimed to provide 1,920 housing units in six 41-storey Concord building blocks, a primary school and a secondary school by June 1999. The domestic developments in Phase 1 were subsequently named Tin Chung Court (TCC). In this Report the term "TCC" stands for the domestic developments in Phase 1 only, the layout of which is shown in Appendix 3. 2.2 Listed as a fast track project by the Housing Department (HD) in 1994, the piling works of TCC were scheduled for tender in May 1996 and completion in July 1997. To expedite the project, standard designs of building blocks were adopted. Concord 1 Option 1 blocks were used in the case of TCC. According to HD's practice, for projects of standard-design building blocks, formal approval of their design is not required, as the architectural and structural requirements are known and the loading schedule is available. The tender paper on TCC piling works, which recommended the award of the Contract to the lowest tenderer, Franki Contractors Ltd. (renamed B+B Construction Co. Ltd. (Franki (B+B)) in March 1997), was endorsed by HA's Building Committee (BC) on 22 August 1996 under the "straightforward papers" approval procedure 1 without discussion. 2.3 The piling works for TCC commenced on 12 September 1996 and were completed on 6 July 1997 as scheduled. The chronology of important activities of the project is set out in Appendix 4. 1 The "straightforward papers" approval procedure was introduced in July 1996. Under the procedure, where the matters to be considered by BC were regarded by HD as non-controversial, they were classified as straightforward items that required no discussion by BC unless requested by a BC member at least one day before the relevant meeting. - 4 - Legislative Council Select Committee on Building Problems of Public Housing Units 2.4 In August 1999, the Consultant Architect of the project, Hsin Yieh Architects & Associates Ltd. (HYA), reported uneven foundation settlement at Wings 2 and 4 of Block 1. HA appointed C M Wong & Associates Ltd. (CMW) to conduct an independent investigation into the structural adequacy of the foundations and the effect of foundation settlement on the superstructures in Phases 1, 2 and 3, Tin Shui Wai Area 31. According to the findings of CMW, based on the monitoring readings up to 15 November 1999, the projected long-term overall uneven settlement revealed a magnitude of 1 in 200 for Block 1, 1 in 353 for Block 2, and 1 in 388 for Block 4. The projected long-term localized uneven settlement was 1 in 242 for Wing 2 of Block 2 and 1 in 304 for Wing 1 of Block 4. The readings in respect of Block 1 and Wing 2 of Block 2 exceeded HA's permissible differential settlement ratio of 1 in 300 2. Restoration and strengthening works for Block 1, and strengthening works for Blocks 2 and 4 were recommended by CMW. 2.5 In January 2000, in response to a request by the HA-appointed Investigation Panel on Accountability in the case of Tin Chung Court, Tin Shui Wai, CMW undertook a desk-top study on the as-built piling records contained in the Registered Structural Engineer (RSE) Report for the project. The study concluded that the actual pile lengths of 60.3% piles in Block 1 were shorter than the pile lengths calculated from the cut off and pile toe levels as shown in the as-built piling records. Acting on behalf of HA, Johnson Stokes & Master (JSM) appointed CMW in May 2000 as an expert witness in relation to legal proceedings regarding the TCC case. For the purpose of instituting legal actions, JSM instructed CMW on 28 September 2000 to co-ordinate investigatory works to ascertain the founding depths of a number of piles at Blocks 1 and 2. From November 2000 to November 2001, 30 piles of Blocks 1 and 2 were drilled to establish their founding depths and 80 piles were excavated to expose their upper sections and connection to the pile caps. The results of drilling works showed that the lengths of 28 piles were shorter than those as recorded in the as-built piling records. Of the 80 piles excavated, 78 were found to have a satisfactory connection with the pile cap but two were 2 Under the Specification, the relative settlement of piles should not exceed 1 in 300 times the distance between the centre lines of the piles. In other words, if the magnitude of relative settlement between two adjacent piles is shown to be 1/299 or more of the distance between their centre lines, it would exceed the permitted limit of 1/300. - 5 - Legislative Council Select Committee on Building Problems of Public Housing Units found to have defects in the exposed lengths. These two piles were then drilled to their founding depths and their lengths were found to be shorter than those as recorded in the as-built piling records. In summary, the lengths of a total of 30 piles were found to be shorter than their recorded lengths as shown in Appendix 5. 2.6 On 12 October 2001, ICAC charged five employees of Franki (B+B), one employee of the Geotechnical Sub-consultant and three site staff employed by HYA on behalf of HD for conspiracy to defraud, corruption, and using false documents. 2.7 The charge against one of the employees of Franki (B+B) was withdrawn on 21 June 2002. Another employee of Franki (B+B) was acquitted on 2 June 2003. On 17 October 2003, one employee of Franki (B+B) and one site staff of HYA were convicted of conspiracy to defraud. The other five defendants were found not guilty. On 31 October 2003 the two convicted defendants were each sentenced to seven years' imprisonment. They have respectively lodged an appeal against both conviction and sentence. At the time of finalization of the Report, their appeals have not yet been heard. 2.8 In April 2002 strengthening works for Block 2 were completed. Restoration and strengthening works for Block 1 were completed in June 2003. In view of public concern about the circumstances leading to uneven settlement of some of the TCC blocks, the Select Committee gave special attention to the design and construction process, in particular the safeguards and control mechanisms in ensuring quality in the process, as well as the inter-relationship among the various parties concerned in their supervision of the works and verification of the designs in ensuring safety of the foundations. Management structure for the project 2.9 TCC was one of the 22 housing projects outsourced to architect-led multi-disciplinary consultants between October 1995 and June 1996, shortly after HD anticipated that some 70,000 units would have to be produced each year in 1999/2000 and 2000/01. According to the Quality Management - 6 - Legislative Council Select Committee on Building Problems of Public Housing Units System of the Housing Department Works Group, the full normal services provided by architect-led multi-disciplinary consultants in an outsourced project cover the following stages of works: Work Stage A - Inception Work Stage B - Feasibility Study Work Stage C - Outline Schematic Proposals Work Stage D - Project Design Work Stage E - Contract Documents Work Stage F - Building Construction For the TCC project, HD was responsible for the outline schematic proposals, planning and budget, i.e., Work Stages A to C, whereas Work Stages D to F (excluding the design and construction drawings for standard-design building blocks) were outsourced to HYA, the Consultant Architect. Project management prior to the appointment of the Consultant Architect 2.10 Up to and including the Outline Schematic Proposals Stage of the project, TCC was under the management of a chief architect of HD, who was the Design Team Leader responsible for the preparation of the master layout plan and the development budgets in the client brief, control plan and project estimates. The Design Team was multi-disciplinary, comprising an architect, a structural engineer, a geotechnical engineer, a civil engineer, a building services engineer and a quantity surveyor. It was responsible for the initial design work which referred to the overall layout of the blocks based on the findings of the preliminary site investigations. The client brief, control plan, scheme design, project budgets and estimates were submitted to, revised and approved by BC during the period from September 1995 to March 1996. 2.11 Prior to the appointment of the Consultant Architect, the Geotechnical Engineering Section of HD was responsible for identifying the geotechnical constraints of the site and providing geotechnical advice and design parameters during the course of developing the overall architectural layout. Acer Consultants (Far East) Ltd. (Acer) was engaged by HD to conduct a geotechnical assessment study on TCC, alongside with other phases - 7 - Legislative Council Select Committee on Building Problems of Public Housing Units of Tin Shui Wai Area 31. The study was conducted in two phases: first between July and November 1994 and second between January and March 1995. In late 1995, Acer was commissioned by HA again to undertake foundation studies for the housing developments in various phases of Tin Shui Wai Area 31 and compiled a Foundation Advice Report (Acer Report) for Phase 1.

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